1. Field of the Invention
The present invention relates to a synchronizing device of a manual transmission applied to a vehicle. More particularly, the present invention relates to a synchronizing device of a manual transmission which prevents abrasion of a blocking key by lowering surface pressure of the blocking key to a locking groove of a sleeve.
2. Description of Related Art
Generally, a transmission is a part of a power delivery device. The transmission is disposed between a clutch and a drive shaft so as to increase or decrease engine torque according to a driving condition of a vehicle. In addition, the transmission has a reverse device for reversing the vehicle.
A synchronizing device of a manual transmission prevents shift shock through a smooth connection of gears by engaging a driving gear with a driven gear after rotation speeds of the driving and drive gears are synchronized when the driving gear is engaged with the driven gear.
FIG. 1 is a partial perspective view of a conventional synchronizing device.
Referring to FIG. 1, a conventional synchronizing device includes a clutch hub 2, a sleeve 4, a blocking key 6, a blocker ring 8, and a clutch gear 10.
The clutch hub 2 is splined to a rotation shaft, and a plurality of recesses is formed at an exterior circumference thereof along a circumferential direction with even distances.
The sleeve 4 is splined to the exterior circumference of the clutch hub 2 and is movable in an axial direction. A sliding recess 12 is formed at an exterior circumference of the sleeve 4, and the sleeve 4 can move to the left or the right in the drawings by a shift fork inserted in the sliding recess 12.
Each blocking key 6 is disposed in the plurality of recesses formed at the external circumference of the clutch hub 2 along the circumferential direction thereof with the even distances
A spring 14 is interposed between the blocking key 6 and the clutch hub 2, and the blocking key 6 is inserted in a locking groove 16 formed at an interior circumference of the sleeve 4 by elastic force of the spring 14.
The blocker ring 8 is typically called a synchronizer ring. The blocker ring 8 is disposed at both sides of the clutch hub 2 so as to protect the blocking key 6 and is adapted to be pushed by the sleeve 4 when the sleeve 4 moves in the axial direction so as to be frictionally synchronized with a cone portion 18 of the clutch gear 10.
The clutch gear 10 is integrally formed with a speed gear.
According to the synchronizing device, if the sleeve 4 is moved to the left or to the right in the drawing for shifting, the blocking key 6 as well as the sleeve 4 moves and pushes the blocker ring 8 to the clutch gear 10.
Then, an interior circumference of the blocker ring 8 is rubbed with the cone portion 18 of the clutch gear 10 such that rotation speeds of the clutch gear 10 and the blocker ring 8 are synchronized. If the sleeve 4 moves further at this state, the sleeve 4 and the clutch gear 10 are engaged with each other and power delivery is achieved.
FIG. 2 is a partial perspective view of an interior circumference of a sleeve applied to a conventional synchronizing device.
Referring to FIG. 2, a reference numeral 20 represents the locking groove formed at the interior circumference of the sleeve 4 and receiving the blocking key 6 therein.
The locking groove 20 is formed at a middle portion of a groove gear 22 among gears forming splines at the interior circumference of the sleeve 4. The locking groove 20 has a concave shape.
In addition, a size of the groove gear 22 is the same as that of a normal gear 24.
Since the size of the groove gear 22, however, is the same as that of the neighboring normal gear 24, a width of the locking groove 20 receiving the blocking key 6 therein is not large.
FIG. 3 is a side view of a blocking key with an assembled state for explaining problems of conventional arts.
Referring to FIG. 3, since the width of the locking groove 20 of the groove gear 22 is narrow as described above, a contact area between the blocking key 6 and the locking groove 20 is also small. Therefore, high surface pressure is applied when shifting, and abrasion may occur if a surface pressure larger than a pressure calculated from an allowable surface rigidity is applied.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.